The goal of this program is to create miniature, low-power neural signal recording headstages with short-range digital RF telemetry. These systems will provide untethered recording capabilities for up to 128 extracellular microelectrodes for animals as small as mice and rats, and up to 256 channels for larger animals. The systems will also allow recording of both local field potentials and extracellular spikes. The devices will use an innovative combination of custom analog ASIC and commercial digital components. In Phase I, the feasibility of the technical approach will be demonstrated by building functional 32-channel systems. In Phase II, these devices will be finished as products for the neuroscience research community. The final base station receiver will be highly programmable to allow use of the system with stand-alone PCs and/or other third-party neural signal processing systems. The real-time interface and PC processing software will be made available as Open Source to facilitate easy customization. These systems will improve the convenience of neuroscience experiments with microelectrode arrays, and enable data from large numbers of electrodes to be collected in free-moving and behaving animals. This project will indirectly support public health by improving the flexibility, quality and efficiency of experiments used for neuroscience and neuroprosthesis research. [unreadable] [unreadable]